Coin control telephone system



June 14, 1960 E. H. GATZERT ETAL 2,941,037

com CONTROL TELEPHONE SYSTEM original Filed July 2e, 1955 15 Sheets-Sheet 1 WN thbmqmw. QIHZOU Z`OU June 14,1960 E. H. GATZERT EVAL 2,941,037

com CONTROL TELEPHONE SYSTEM Original Filed July '26, /1955 15 Sheets-Sheet 2 15 Sheets-Sheet 3 alii.

E. H. GATZERT ETAL com CONTROL TELEPHONE SYSTEM original Filed July yze, 1955 June 14, 1960 June/14, 1960 E, H GATZEKRT ETAL 2,941,037

COIN CONTROL TELEPHONE SYSTEM Ofiginal Filed July 26, 1955 l5 Sheets-Sheet 4 June 14, 1960 E. H. GATZERT ETAL COIN CONTROL TELEPHONE SYSTEM Driginal Filed July 26. 1955 15 Sheets-Sheet 5 Ou h 53.0 xuQ.-

lill llll June 14, 1960 E. H. GATZERT ETAI- 2,941,037

com CONTROL TELEPHONE SYSTEM Original Filed July '26 1955 l5 Sheets-Sheet 6 June 14, 1960 E. H. GATZERT EI'AL 2,941,037

com CONTROL TELEPHONE SYSTEM original Filed July 2e, 1955 15 sheets-sheet 'r l X mmw ZOCQhmxQl I.

:SEAN NSE June 14, 1960 E. H. GATzER-r TAL 2,941,037

COIN CONTROL TELEPHONE SYSTEM Original Filed July 26, 1955 15 Sheets-Sheet 8 N .wrm

m` .23015 vtfbth s QSL.

mwmm @5.33

Too

June 14, 1960 E. H. GATzER-r rAL com CONTROL TELEPHONE SYSTEM original Filed July ze, 1955 15 Sheets-Sheet 9 JCC n w H m 8 c G. l K l. N l u. U F R T n w .l||--||10 l n l l 1 l 1 n l: w T

3 2 a i m c f .w

HsLPmsi June 14, 1960 E. H. GATZERT UAL 2,941,037

` COIN CONTROL TELEPHONE SYSTEM Original Filed July 26, r1955 l5 Sheets-Sheet 10 l I l l l l l l l l l l l l i914 #als l l l R d 0 LW. a 9 .m n. mum M iwi A 9:9 Mil-III 9M.. 9 {Hifi} il l. J Y n i x 9 9 u M mm M MESSAGE SUPERVISORY CONNECTOR 2l V T5851 FIG. 9

June 14, 1960 E. H. GATzER-r ETAL 2,941,037

COIN CONTROL TELEPHONE SYSTEM Original Filed July 26, 1955 15 Sheets-Sheet l1 T. mmoT A N tOHOwZZOU Eind June 14, 1960 E, GATZERT ETAL COIN CONTROL TELEPHONE SYSTEM Original Filed July 26, 1955 15 Sheets-Sheet 12 fza i (+I-'0T-x/IH T6 T4 *I* u Re R4 n u INCOMING SELECTOR -i STARR -IIOV REFUND IPAYsTATloN l ToNE I ll2.2 1 Two wAY TRUNK c/Rcu/T'ls ,IF-W c,

| FIG. ll PEG couNT: [L ,5

FIG, l FIG, 2 colN CONTROL SELECTOR 24 F IG. I4

FIG. 3 FIG. 4

FIG. 5 FIG.6 FIG. 7 FG.

FIG. FIGJO FIG. FIG.I2

LOCAL AND ToLL l v coNNEcToR 21 F16 3 \Two wAY TRUNK clRculT /9 15 Sheets-Sheet 13 E. H. GATZERT ETA!- COIN CONTROL TELEPHONE SYSTEM June 14, 1960 Original Filed July 26,

June 14, 1960 E H, GATZERT ETAL 2,941,037

COIN CONTROL TELEPHONE SYSTEM Original Filed July 26, 1955 15 sheets-smeet 14 NE ZQW 15 Sheets-Sheet 31.5v

June 14, 1960 E. H. GATZERT x-:TAL

com CONTROL TELEPHONE SYSTEM Original Filed July 26, 1955 United States Patent C COIN CONTROL TELEPHONE SYSTEM Ernest H. latzert and William W. Pharis, Rochester, N.Y., assignors to General Dynamics Corporation, Rochester, N. a corporation of Delaware 2 Claims. (Cl. 179--6.3)

This invention relates to telephone systems and more particularly to coin control systems for use therein.

It is old to provide telephone systems for use in connection with paystations. The operator, in such systems, controls the disposition of coins which may be deposited in the coin box of the telephone to pay the charges required for the completion of a toll call. Sometimes this control feature is arranged so that an operator at a central oflice may control the disposition of coins at a remote oice, such as in a community dial oi`n`ce or the like, for example. In this case, it is necessary to provide means whereby the operator may control ofiice equipment in the community dial oice. The present application is a division of copending application Serial No. 524,520, now Patent No. 2,897,272, tiled July 26, 1955, entitled Coin Control Telephone System, and assigned to the same assignee as the present invention.

A rst object of this invention is to provide a new and improved coin control telephone system.

A second object of this invention is to provide a coin control telephone system where an operator at a central oce may control the disposition of coins at a remote o ce.

Another object of this invention is to provide coin control in a four-wire telephone system.

Still another object of this invention is to provide a new and improved coin control trunk circuit.

Still another object of this invention is to provide a new and improved toll and local connector for use in a coin control system.

The above described lobjects are accomplished by means of a telephone system wherein a remote office includes a trunk circuit which may be usedl on Aeither incoming or outgoing calls. In the case of outgoing calls, a telephone connection may be extended from the remote oice through a trunk circuit to an operator at-a central or distant oiice. In the case of incoming calls, the trunk circuit may be used to extend a telephone connection from the operator at the central or distant oilice to a local switch train in theremote otlice. The local switch train in the remote oice includes a connector having four sets of incoming terminals over which the connector may be seized upon the extension thereto of the incoming call from the trunk line. When the connector has been directively operated by the operator and made to seize a called telephone line in the remote ofiice, two o f the terminals are included in means for conducting voice currents between the operator position and the called telephone line, while the remaining two terminals are ineluded in means for controlling the connector. One of the latter two terminals and the aforementioned connec-y tor controlling'means in which it is included is used for marking or identifying the incoming call as being of either toll (i.e., from an operator position) or local (i.e., from a 'subscriber telephone line in the remote oflice) origin. Means within the connector controlled over this one marking terminal is used for controlling the establishment of a coin control circuit through the connector ice upon the receipt of coin control supervisory signals from the operator position. The connector also includes-means eiective over this one control terminal for returning answer and `busy supervision from the called subscriber line to the operator position'. The connector is further equipped with a busy test relay and means for operating the busy test relay at one time during the sequence of setting up a call if thecalled line is busy. Other means within the-connector is provided for operating the busy test relay at a dilierent time in the sequence setting up the call for applying ringing current to the line, and still other means including the connector coin control responsive means is effective for operating busy test relay at a still different time in the sequence of setting up a call for holding the conversion circuit. Y

It is thought that these and other objects will be obvious to those skilled in the art and that the invention may be explained best by means of the following description when taken in connection with the attached drawings in which:

Fig. la shows by block diagram a telephone sy'stem using the coin'control features. Items l19, 21 and 24 of this block diagram are in heavily inked rectangles, thus indicating that they are the circuits shown in detail in the remainder of the drawings;

Figs. 1-4 show a coin control selector; Y Y

Figs. 6-8, l1 and 12 show a two-way trunk circuit;

Figs. 5, 9, 10 and"13 show' details of aflocal and toll connector; Y 7' Fig. 14 shows the manner inv which4 the foregoing iigures should be arranged to provide a complete and understandable circuit; and

Fig. 15- shows a skeletonized circuit V.based upon detailed drawings. The parts and components of this drawing have the same reference numerals as the same parts in the detailed drawings.l It is thought that this gure will explain the fourth wire control with greater efficiency.

The source of potential is shown in the drawings by plus and minus signs. As in the case of most telephone circuits, the plus potential is described as connected Vwith ground and the minus v( potential is described as battery. It should be understood that this or any other suitable source of power may beus'ed.

BRIEF DEsCRIPrioN This invention may be explained brielly by making reference to Fig, la. This figure shows by block diagram a telephone system adapted to use the coin control features of the invention. For example, the subscriber at paystation 10 may initiate a telephone call by removing his receiver or handset 'and depositing a required coin. Allotter 15 causes line nder 1'2 and line circuit 11 to cooperate to nd the calling line `which is extended through selector 14. The next telephone function depends upon the ultimate destination of the call. `For example, digit pulses 'transmitted from paystation 10 may cause local first selector 14, second selector 16 and connectorZlvto seize and signal paystation 23. On the other hand, selector 14 may be directed to a particularlevel from which toll calls may be completed, such as the' tenth or zero operator level, for example. In this case, a circuit is completed over conductors 18, two-way trunk .circuit 19, and trunk line ,12S to a distant ofiice. When the operator answers the coin whichlwas deposited at paystation 10 to make the call is returned. Thej operator at position 40may converse with the calling subscriber at paystation 10. Then she instructs himto deposit in the coin box of telephone 10 a certain amount of money depending upon the charges for completing the call.

Operator 40 may use special coin control trunk line 26 and coin control selector 24 to control the disposition of coins at paystation 10. Firstshe directs a switch upper lefthand corner of Figi 6.

associated with selector 24 by means of digit pulses transmitted by any suitable device, such as dial 41,.for example, according to the numerical designation of trunk circuit 19 Vthrough which the call has been extended. For example, if the number oftwo-way trunk circuit 19 is `8 3 the switch is stepped in its primary direction to its eighth level and then in its secondary direction to its Y,third set of terminals to which conductors 27 are attached. VNext, theV operator atv position 40 may pro.-

Y ceed to control the disposition of coins-deposited at pay- The inventive features of this system reside primarily in the coincontroly system extending through selector 24,

Y two-.way trunk circuit 19, and yconnector 21.

Y y DETAILED DESCRIPTION Y v. Call from paystaton 10,710 operator Aposition 40 The rst call tobe described V is originated at paystation 10 andY is completed-through two-way trunk circuit 19 t0 The following digit pulses operator'position 40. Paystation 10 is shownin the' V.,S'err,L`r:e.,-.zrny suitable local switch'train maybe used to seizeconductors 18 which lead to two-way trunk cir cuitVi Responsive thereto, .a circuit is .completed for 'Y operating Vcalling bridge relay `730. The purpose of this "relayV4 is ,to seize the trunk circuitY and toY control the transmission of a seizure signal over the Ytrunk line 2S to switchboard 40 at the-distant otiice. The circuit for operatingcalling bridge relay. 730 Vmay be traced from batterythrough the lower winding ofrrelay 730, rest contacts-762,834, the lower lefthand Vwinding of repeat coilRCSLrestlcontacts `838, 724, 624, vconductor R, the local switch train, paystation 10 where a loop is completed to the tip conductor, and return over the local switch train conductors T, rest contacts 621, 721, 831, the upper lefthand winding of repeat coil RCSI, rest contacts 833 and 761 to ground through the upper winding of calling bridge relay 730. Relay 730 closes its contacts 1231 to operate release delay relay I1240 over an obvious circuit.v It also closes its contacts Y1232 tovoperate helping sleeve vrelay 820 over a'circuitwhich may be traced from battery through operated contacts1232, rest contacts 1267, the upper windingof helping sleeve relay z820 and rest contacts 839a to ground Differential relay 820 .operates since its lower falls. Contacts 1241 close to prepare for the transmission of ring-back and paystation tones. YContacts 1242 close; however, -they have no function until the operator prepares for coinrcontrol. Contacts 1243 close to operate coin ltone relay 1110 over the circuit from battery through the winding of relay 1110, rest contacts 1212, 1224 and operated contacts 1243 to ground Contacts,1 244 close,Y for lightingmonitor lamp MON (Fig. l2) brightly as an indication that the circuit has been seized but has not switched through as yet. The circuit extends from ground through the lament of lamp MON, contacts l1244, 1269, 1225 and the message supervisory conductor to ()v battery, not shown. IIhis feature relates to local supervision for the benet of maintenance personnel. Contacts 1246 close to prepare for peg count or stated otherwise for a trafc survey. Contacts 1247 open to remove the ground marking normally `applied to all-trunks-busy conductor. This conductor is means for indicating whenall trunks in the Yrank including circuit 19 are busy. That is, as each trunk-similar to'circuit 19 becomesV busy, it removes a ground marking normally extended over the all-trunks-busy conductor. When theV last'trunk circuit has become busy, there is no marking on the alltrunks-busy conductor and responsive thereto a register is operated thus recording an overflow condition. Previously, this-marking extended from the all-trunks-busy conductor over. rest -contacts 1247, 1214busy key 'contacts BK61 and rest contacts 766 tof-groundV (-i-f).

Helping sleeve relay 820 operated responsive to the energization of `calling bridge relay 730and `the completionY of a circuit including.,` ground ,(-i-l),V contacts 839e, the uppeipwindingof relay820, contacts 1267, 1232 and battery. This relay Vis used tocontrol the application lof idle lineytermination, to extend a seizure signal to the distant oice andY to'give local supervision. f More particularly, its contacts 823 open to remove the idle line Winding S ShUIlcd, bythe application of ground to both of its terminals via contaets-839a.V

- Release `delay relay 1240 is used to hold `trunk circuit equipment operated, to control Athe release thereof, and tooassist, in certain supervisory functions. In greater deta1l,; release delay relay 1240 operates over Van obvious circuit ywhen contacts 1231 close.'` Responsive thereto,

. contacts 741 close for applying aground (-l-)bu's'ymarking to,l sleeve conductor S. This ground alsolserves to 'hold all `precedingequipment in anoperated condition l until thecall is terminated. :Contacts 742'opento prevent .any-operation'of pulse relay 810on-thisfcall as-it functionson-inco'rning'call's-V only. -Co'ntact's -743 close f' toprepare Vfor control Yof lsupervisory relay'720 from the distant Yoliice; 'Contactsf744 close to 'apply a 'ground (K+) f. marking to master `ground conductor MG'g/'This marking is `used to hold certain equipmentin'an operated V- condition; therefore, when -itf is removed thatV equipment termination normally completed across conductors T vand R. This termination may be traced from conductor T over conductor T2, rest contacts 823, capacitor C81, resistor R81, rest contacts 1264, conductor R2V and conductor R. Contacts 821V vopen and 822V c1os'e,'thereby switching'V conductor M from ground (i) to(-) battery. The batteryis applied through the filament of lamp L81, operated contacts 822, conductor M, the upper winding of signal relay 840, impedance 181 and conductor R3 of trunk line 25, to the distant oice. This marking signals the operator at position 40 thus indica-ting that a call is awaiting her answer. Signal relay 840 is differentially energized at this time so that it does not operate.

u Coin tone relay 1110 operates as explained above. Since it is assumed that the call is from a paystation, this relay isV used at this time to control the refund of the coin originally deposited at the paystation and to transmit tone .indicating that the call originated at a paystation. Contacts 611 open thereby temporarily disabling relay 710 which is not-required at this time. This prepares for the Vcontrol of coin refund. Contacts 1111 closeto prepare a circuit for-'shunt relay 1250. Y Contacts 1112 close to start common interrupter equipment which may be necessary to provide tones and pulses requiredduring the completion of aj'call. Contacts 1113 close'. also rto prepare-for coin ,refundf Contacts 1114 close to complete a circuit for transmitting ring-back'tone to inform the .calling subscriber that lhisdcall is! being completed. This circuit extends from the ring-back tone conductor over rest contacts 1213, 1227,'capacitor C111, operated contacts 1114, 124,1, conductors-R2, conductor R,rrest'cor1tacts 724,l 624, the local Vswitch Vtraimglaystation V10 and return .over'the local switch train, conductorT," contacts 621, 721,L 331V', 'the Vupper lefthand winding of: repeat coil RCSL' contacts 833, 761 and the 'upper'winding' of vrelay 730 to ground 4+);

Operator answers.-Nothing further happens until=the operator at position 40 responds to the seizure signal and answers the call. Responsive thereto, a signal is transmitted over conductor R3, through imepdance 181, the upper winding of signal relay 840, conductor M, operated contacts 822 and the lament of lamp L81 to battery. Now, the direction of current lflow is such that relay 840 operates and closes its contacts 841. Ground (1-) is extended to operate supervisory relay 720 over the circuit including contacts 841, 743, and the lower winding of supervisory relay 720 to battery.

Relay 720 operates as an indication that the operator has answered. Responsive thereto, contacts 721, 722, 724 and 725 operate to reverse the direction of battery ow over conductors T and R. That is, before the operation of supervisory relay 720, battery flow was from battery through the lower winding of calling bridge relay 730, rest contacts 762, 834, the lower lefthand winding of repeat coil RC81, rest contacts 838, conductor R, rest contacts 724, 624, and the local switch train to paystation 10, with return from paystation over the local switch train, conductor T, rest contacts 621, 721, 831, the upper lefthand winding of repeat coil RC81, rest contacts 833, 761, and the upper winding of calling bridge relay 730 to ground (-1-). After relay 720 has operated, this direction of current ow is reversed. Contacts 726 close to extend a resistance battery marking to conductor HS for any suitable supervision purposes which may be required in connection with the local switch train. This circuit may be traced from battery through the resistance of the non-inductive (NI) upper winding of relay 720, rest contacts 753, operated contacts 726, conductor HS, cable 18, and the local switch train to ground (-1-), as required. Contacts 1221 have no eiect at this time since contacts 611 are open. Contacts 1222 comlete an alternate holding path for release delay relay 1240. Contacts 1223 close to operate shunt relay 1250. The circuit for operating this relay extends from ground (-1-) through operated contacts 1111, rest contacts 1211, operated contacts 1223 and the Winding of shunt relay 1250 `to battery. Contacts 1224 open to break the original operating circuit from ground (-1-) at contacts 1243 to coin tone relay 1110. However, it does not release immediately, ldue to the charge stored on capacitor C113. This feature will be explained below in the section entitled Paystation Tone.

Heretofore, monitor lamp MON (Fig. 12) glowed brightly over a circuit which was traced from ground (-1-) through the iilarnent of lamp MON, operated contacts 1244, rest contacts 1269, 1225 and the message supervisory conductor to a battery, not shown. Now, after relay 720 operates contacts 1225, the lamp glows dimly over a circuit which may be traced from ground (1-) through the' filament of monitor lamp MON, operated contacts 1244, resistor R121 and the message supervisory conductor to battery, not shown. Contacts 1227 open to terminate ring-back tone and 1226 close to prepare for paystation tone. Contacts 1228 close to extend a marking to the peg count conductor thus giving a tra'ic survey of the number of times :that the trunk is used. This circuit may be traced from the peg count conductor through operated contacts 1115, 1228, 1246, rest contacts 1214, busy key contacts BK61 and rest contacts 766 to ground (-1-).

Automatic refundshunt relay 1250 operates. The reason for operating it at `this time is to control coin refund. Since it is assumed that the call originated in a paystation, conductor HS is marked by ground (1-). On the other hand, if the call had originated from other than a paystation, there would be no ground marking on conductor HS. This ground marking is extended from conductor HS through contacts 726 and 752 to battery through the upper winding of paystation relay Relay 620 operates to refund the coin that was deposited to originate the call. Preliminary or X contacts 626 close when relay 620 is energized over its upper winding. The circuit for holding operated relay 730 includes contacts 621 and 624 which are about to be opened. Hence, the operator will receive on-hook supervision during automatic refund which makes it appear that the calling subscriber has hung up. As will be pointed out presently, after automatic refund relay 730 will be held in an operated condition once more from the calling subscribers station. Thus, the on-hook supervision is merely -a ash. Sometimes this ash s required and sometimes it is unwanted. Therefore to eliminate ash supervision, relay 620 closes its X or preliminary contacts 623 to complete yan alternate holding circuit for relay 730 if wiring C is provided. This circuit extends from battery, through the lower winding of relay 730, contacts 623, 713, 723, wiring C, resistor R72, contacts 761 and the upper winding of relay 730 to ground (-1-). If wiring C is omitted, this path is open and ilash supervision is given. A circuit is completed from ground (-1-), through operated contacts 744 and 626 to battery, through the lower winding of relay 620. Relay 620 is locked when energized over this circuit. Paystation relay 620 closes its contacts 622'and 625 thereby extending refund battery to operate the paystation mechanism, thus refunding the coin that was deposited Ito initiate the call. This refund battery may be traced from conductors T and R, through operated contacts 622 and 625 in parallel, rest contacts 711 and 714 in parallel, operated contacts 1113 and the filament of lamp L111 to 110 volt refund battery. Contacts 1121 close; however, they have no eiect at this time since contacts 1224 are open.

Paystazion tone. -It should be recalled that relay 840 operated responsive to the receipt of answer supervision from the distant oice. Contacts 841 closed and since release delay relay 1240 was operated at this time, supervisory relay 720 operated. It opened its contacts 1224, thus breaking the original energizing path to coin tone relay 1110. It should be noted that capacitor C113 was charged prior to the opening of contacts 1224. This charging path extended from battery, through capacitor C113, rest contacts 1212 and 1224 and operated contacts 1243 to'ground (1-). This circuit is open at contacts 1224. Capacitor C113 begins to discharge through the winding of coin tone relay 1110. Therefore, relay 1110 remains in an operated condition for a brief interval of time after the operator has answered. During this interval, a circuit is completed from the paystation tone conductor, through operated contacts 1122, 1226, capacitor C111, contacts 1114, 1241, conductor R2, rest contacts 833 and repeat coil RC81 to the distant exchange. This vtone informs the operator that the call was originated at a paystation.

If the operator should fail :to hear the paystation tone and wish to verify, she will disconnect thereby releasing signal relay 840 which in lturn opens its contacts 841 to restore supervisory relay 720. Contacts 1224 close and coin tone relay 1110 reoperates. The charging path is completed for recharging capacitor C113. When the operator reconnects atthe distant end, supervisory relay 720 reoperates opening contacts 1224. Responsive thereto, coin tone relay 11110 is held briey by the discharging current from capacitor C113 in the manner explained before.

When coin tone relay 1110 releases, it opens contacts 1111 thereby'restoring shunt relay 1250. Previously, this relay has been operated over the path which includes ground (-1-), contacts 1.111, 1211, 1223, the Winding of, relay 1250 and battery. Shunt relay 1250 releases. Responsive thereto, a circuit is completed for operating coin refund relay 710 over the circuit which may be traced from battery, through the winding of relay 710, rest contacts 718, 611, 1251, operated contacts 1221 and 744: to ground (A+). This removes the Y manos?,

coinrefund; batteryformerly lextended .from 110 volt' refundzbattery` throughllamp L11'1', contacts 1113 and in parallel over contacts 711 and 714, contacts 622 and 625, Ycable 18 andthe Ylocal switch train to paystation 10. YContacts 712 and. 715- also complete the talking circuit. fromcable 18 over conductors T' and R to repeat coil RC81; YContacts 712 and 715 are X contacts which close before contacts 713 open to hold relay 730 positively during transfer. time of the contacts. After coin refund. relay 710 is operated, it locks at its contacts 717'to master ground conductor MG so that if cointone relay 1110 is reoperated to reapplyY coin tone, coin refund relay 710 will not restore. Contacts*Y 1212 opensothat' coin tone relay 1110 depends for its reoperation Vupo'n the continued operation of paystation relay 620;.0 Contacts`1213 open so that ring-back tone will not bev returned if the operator veries the paystation tone by causing supervisory'relay 720 to drop and reclose contacts 1227;` .Contacts 1214 open to prevent a second Y peg. count if. theV operator ver'ties paystation tone.k

' Coin conzrol.-The operator conversos with the calling vsubscriber and determines the destination of the call.

After this she computes the charges for the completion of such calls and instructs the calling subscriber to deposit therequired amount of money. Thereafter, the

operator at positionY 40 seizes a coin control trunk line 26 which has access to a'coin control selector 24. After Ythe operator has seized coinY control trunk line 26 and hasv completedwa circuit through conductors CCT and YCCR (the upper lefthand portion of Fig. l), reverse battery is. applied in the distant oice to conductors .CCT and CCR. YThis closes Va circuit for operating pulse relay 1'10. This relay controls the mechanical driving of the switch responsive to the receipt ofdigit pulses. ,Con

tacts 311 close thereby operating release delay relay 360 overthe path from ground through operated con- `tacts 311,5the.;.winding of release delay'relay 360 and release magnet interrupter contacts RE41 to battery. A; circuit isalso completed. from ground through operated contacts 311,4 resting primary ott-normal contacts PON33 and theupper Winding of primary Y delayrelaySG-to battery. Contacts 111 close to lfmtfircomaasV 361 Vana 41116 (Lybaneryzthrough "the Vpulse which is a break inthe loop circuit including con ductorsV CCT V`and CCR. Responsive to Yeachdigit pulse, relay 110releases to Vopen contactsi311"and^to' close contacts 312. This Ydeenergizes releaseY delay relay :360; however, it does not release throughout digit pulsing" due to its slow release characteristics. Eachtime .that contacts 312 are closed, a circuit is completed foroperating primary f stepping magnet P thereby causing .the switch to beV driven one step Yin its `'primary direction for-.each digit pulse. rlhe circuit for this functionextends from ground through Vre'st contacts 312,"opera'ted con` tacts 161', 215, 183, the lower winding of relay 380 and primary magnet P in'parallel to battery.Yr Primary oilnormal "contacts 'PON31', PONSZ:Y and PON33 are operated responsive to the rst stepof the switch in the primary direction. YWhen contactsPONSS open, the original energizing circuit for primary delay 'relayVV 330 is broken; howeventhis relay doesA notrlease since Vit is energized over its lower. winding each time that a digit pulse is received.' /Relay 380 'is slowetorelease; therefore, itY continues to hold'througlout. digit pulsing land releases only after the last pulse in the digit pulse train has been received. 1 VPulse relay 110 followsl the remaining digit pulses. It opens and closes the circuit'to primary delay'relay 380 and-primary stepping magnet P responsive to each digit pulse. Therswitch is ydriven one step on each pulse.V On completion of the digit pulse'train', a loop across conductors CCT and CCR remains closed'longgenough for primary delayrelay V380 to restore. It opens contacts 183 and closes contacts 182 thereby transferring the pulsing path from the primary to'the secondary magnet.'

prepare Ya verification tone circuit so that the operator Y may know that 'she lhas dialed the correct trunk circuit.

Release delay relay 360 operates. 'The purpose of this relay is to holdathe circuit throughout digit pulsing, to control'V release and to provide certain local supervisory features. When this relay operates, it closes its contacts 162y to extend Va circuit from ground through secondaryfoi-normal contacts SON22, andthe lower Winding of secondary delay relay 210 to battery., Monitor `lamp MON (Fig. 3) is now lit Ibrilliantly as an indicationY thatf-the` coin control selector has been seized Y but has not switched through as yet. The circuit for lighting jthis. lamp extends from ground through operated.V contacts 361 and 427 to lbattery' by way of the filament of lamp MON.(Fig. 3). The release alarm conductor is opened at contacts 363 to prevent anyf faulty or premature release. Contacts 362 close to prepare a'circuit for coin slave relay 460.

Primary delay, relay 380 operates. Thereason for operating' this relay at this Vtime is to mark the end of the rst' trainV of digit pulses that is to be received. Ground l(-} )V is appliedto wiper CO from contacts 181. The pulsing path is prepared at contacts 183.

A Secondary delay relay 210 operates. The purpose of this relayis to mark the end of the second digit pulse train.'VY It completes the prepared pulsing path at its con- Y tacts-215.Y Verification tone conductorA VT is disconnected. at contacts 2171. Contacts 212 close to shut rst coin refund relay 120 andthe lower winding of coin collect 'relayY 140. VVThis circuit is in parallel with contacts Y lightingv lamp MCN (Fig."3) brightly.Y The circuit'rfor thisv function extend'sfrom ground' (Lil) through oper- The switch is now ready to receive the second digit pulse train. Y

vSeconddgt.-Again, each digit pulse is in-the form of a breakin the loop extending across conductors CCT andfCCR. Responsiveto each'break in this loop, pulse relay 1\10frestores to'close*` contacts |121 This, in turn, causes the 'switch to step fin, its 'secondary direction at the rate of one step per pulse. The circuit for this function may be Ytraced from ground V(-1-), through rest contacts 312, operated contacts 161, 215, rest contacts 182, operatedv contacts 216, the upper Winding of secondary delay relay 210 .and the winding of secondary. magnet S in parallel to battery. Responsive to the iirs't'switch step in thelsecondarydirection, secondary offnormal' contacts SON11','SON21, SON22 and SON31 yareV operated. The original` energizing path 'for Sec ondary delay relay 210 is broken when contacts SON22 open; however, this relay does not release'until the end of digit pulsing due to the fact that itt-is a slow release relay-and due to theffact that it receives an energizing'pulse over its upper winding each time that a digit pulse isfreceived. When relay 210 releasesg'contacts 212 open `to remove the shunt from Varound relays and 140. A f' Vz'fcatz'on'tona4The switch is drivento the particular set of terminals whichare desired. These are the terminals which are individual YtoetWo-WayV trunkV circuit 19.` V'After the last digit( pulse has beenreceived, secondary delay relay 210 restores. ThisY connects veriiication tone to the talking conductors in trunk circuit 179 thereby informing the operator that s he has dialed the'correct digit since she is listening over the original connection for. the tone. The circuit for this verication tone may be traced from the high and verification tone conductor contact ,172over restfcontacts 131, l'operatedl contacts 111, rest contacts 211JY conductor VT`to Figo, conductor T, rests contacts 831, tire upper lefthand winding ofrepeatcoil RC81, rest contacts 833, 761 and 4the upper winding of calling bridge relay 730 to ground I'his tone is induced in the righthand windings of repeat coil R081 and transmittedv over cable 25 to operator position 40.

Monitor lamp MON (Fig. 3) is caused to burn at a reduced level of illumination due to the fact that contacts 417 are open and the energization circuit for lamp MON now extends through resistor R31. This is an indication that the coin control selector has switched through. A circuit is prepared for cutoff relay 220 when contacts 214 close. Contacts 213 close to energize coin collect relay 140. 'I'he circuit for this function extends from battery through the upper winding of coin collect relay 140, rest contacts 213, operated secondary off-normal contacts SON21 and operated rest contacts 162 to ground Coin collect relay 140 does not operate because it is diierentially energized, the upper winding being energized over the previously traced circuit from ground on contacts V162 and the lower Winding being energized in series with conductors CCT and CCR. However, coin refund relay 120 does operate in the loop including conductors CCT and CCR extending to the distant oice. It closes its contacts 121 thereby operating a second coin refund relay 130. Coin refund relay 130 is slow to operate so that a brief interval transpires during which the verification tone is transmitted in the manner explained above to the operator at position 40. After this brief interval, the tone circuit is broken at contacts 131. Contacts 133 close to prepare a circuit for cutoi relay 220. This circuit is not effective at this time since contacts 312 are now open.

The circuit is now prepared for coin control; therefore,

the next circuit functions depend upon the sequence of events which may have transpired heretofore. For example, if the calling subscribed deposited a proper amount, the operator may proceed to collect the coins at this time. `On the other hand, there may be occasions when she would proceed to refund the coins.

Coin collect.-The operator at the distant oice depresses a proper key for controlling coin collection. The direction of battery flow over conductors CCT and CCR is reversed. This reverses the direction of battery flow through the lower winding of differential coin collect relay 140. The flux in the lower winding of relay 140 now aids the iiux in the upper winding thus causing the relay to operate. Contacts 141 close thereby operating a second coin collect relay 150.

Relay 150 operates and closes its contacts 152 thus causing thermistor IlHZl to heat. This device is arranged so that its resistance goes down as a function of time over which it is heated. Hence, over Ithe brief interval of time when thermistor TH21 is heating, cutoff relay 220 does not receive enough current to operate. However, after the expiration of this brief interval of time, relay 220 will receive enough current and will operate. Contacts 351 close to prepare the path for applying coin collect battery while contacts 352 open to break the path' for applying coin refund battery. Contacts 353 close to operate coin collect relay 370.

When relay 370 operates, it prepares a path for extending a special tone to conductor CT. This tone path may be traced from a low Itone conductor through contacts 371, '171, 222 and 261 (both of which are now open) to conductor CT. 'The lower tone provides a distinctive coin collect signal.

By this time, thermistor r11H21 will have heated sufliciently to cause cutoff relay 220 to operate. It closes its contacts 223 thereby by-passing and protecting thermistor TH21. -A ground marking is applied through X or preliminary contacts 221 to cutoff conductor CO. This ground marking is extended to trunk circuit 19 and over operated contacts 1242 to energize cutoff relay 830.

Relay 830 opens contacts 839a and closes contacts 839b, thereby switching the marking extended to conductor H84 through the upper winding of helping sleeve 10 relay 820 4from ground on contacts 839a to battery on contacts 1245. This has no effect in this paratcular call. Contacts 832 and 839 close thereby placing a short circuit across conductors T and R. Contacts S31 and S38 open thereby breaking the talking connection to repeat coil RC81. This is in preparation for the application of collect or refund potential to the talking conductors. Contacts 833 and 834 open to break the connection to calling bridge relay 730; however, it does not release at this time because a holding path is completed over the following circuit: from battery, through the lower winding of calling bridge relay 730, rest contacts 762, operated contacts S36, resistor R72, rest contacts 761 and the upper winding of calling bridge relay 730 to ground It should be noted that contacts 836 are preliminary or X contacts which are adapted to make before contacts 833 and 834 break thus furnishing a posi tive holding circuit for calling bridge relay 730.

A distinctive tone is now transmitted to the operator, informing her of the fact that a coin control potential is applied to conductors T and R. This distinctive tone may be traced from the low tone source through contacts 371, 171, operated contacts 222, control tip conductor CT, operated contacts 835, the lefthand windings of repeat coil RO81 and operated contacts 837 to ground through capacitois C32. This tone is repeated through repeat coil RC81 to the operator at position 40 in the distant exchange.

Returning to the operation of cutoff relay 220, it also closes its contacts 421 thereby applying a ground potential to the start conductor. This initiates the operation of suitable common equipment which furnishes various tones, pulses and currents that are necessary to complete thev call. A circuit is completed at contacts 422 for holding coil collect relay 370 in an operated condition. This holding circuit includes contacts 372 and 422. Contacts 423 close to prepare part of a holding circuit for various relays in the coin control selector. lResponsive thereto, coin slave relay 460 operataes, its energizing circuit being traced from battery, through the Winding of relay 460, operated contacts 362, rest contacts 464, 451, and operated contacts 423 to ground Relay 460 operates to control the disposition of the coin. An alternate path is closed at contacts 261 for applying the low tone indicating collection over the talking trunk to the operator. A circuit is also completed for operating primary delay relay 380. This circuit may be traced from battery, through the upper winding of primary delay relay 380, operated primary ofi-normal contacts PON32, operated contacts 262, operated secondary off-normal contacts SON21, and operated contacts 162 to ground The upper winding of start relay 440 is connected at contacts 461 to a 60 i.p.m. conductor. The lower winding of start relay 440 is energized through an obvious circuit including contacts 462. A holding circuit for lockout relay 450 is prepared at contacts 465.

Start relay 440 is used to start the period during which the coin control potential is applied to the line.- If a ground pulse is'present on the 60 i.p.m. conductor when start relay 440 is connected thereto, it will not operate because it is then differentially energized due to the current flowing inthe upper and lower winding with the magnetic flux in the two windings opposing each other. This prevents the sending of an initial pulse of coin control voltage which is too short to operate the coin collecting mechanism at the paystation. When ground is removed from the 60 i.p.m. conductor, start relay 440 operates Aover its lower winding, the upper winding being then deenergized. A locking vcircuit for coin collect relay 1.50 is Ycompleted at contacts 241 and contacts 151. yAn alternate ground marking is applied to the start conductor at Acontacts 442. A path is prepared at contacts 441 for extending coin collect battery. Contacts 444 close to place coin interrupt relay 430 under the control of the 60 

